The primary objective of the post-CABG study is to determine the effects of intensive LDL cholesterol therapy alone, low dose warfarin therapy alone, and the two in combination on wall changes as a result of progression or regression of atherosclerosis or as a result of the presence of thrombus in saphenous vein graphs and native coronary arteries over a period of five years. Other objectives will be to assess the treatment effects on cardiovascular mortality, non-fatal MI, repeat revascularization, and total mortality.